Activists in Oregon announced a signature gathering campaign to place a ballot measure requiring the labeling of genetically modified foods on the statewide ballot in November on May 15, 2014. (KOIN 6)

PORTLAND, Ore. (AP) — Activists in Oregon have announced a signature gathering campaign to place a ballot measure requiring the labeling of genetically modified foods on the statewide ballot in November.

If adopted, the initiative by Oregon GMO Right to Know would require food manufacturers, retailers and suppliers to label raw and packaged foods produced entirely or partially by genetic engineering. The measure would not apply to animal feed or food served in restaurants. It would be effective January 2016.

More than 87,000 signatures are needed to qualify for the ballot. The group has until July 3 to collect signatures.

Signature-gathering is also underway in Colorado and in Arizona to put up similar labeling measures.

Unlike dozens of other countries, the U.S. currently does not require the labeling of genetically engineered foods. But the use of GMOs has been a growing issue of contention in recent years, with American consumers, environmentalists and health advocates pushing for mandatory labeling.

Earlier this month, Vermont became the first state to pass a law that requires labeling of genetically modified organisms. The law takes effect in mid-2016.

Maine and Connecticut have enacted labeling laws for engineered foods, but those won’t go into effect until other states in the region follow suit. Counties in Hawaii, Washington state and California have adopted laws banning or limiting genetically modified organisms.

There are currently 85 bills on GMO labeling in 30 states, with more than half introduced this year, according to the National Conference of State Legislatures, as well as dueling bills in Congress.

Two recent labeling ballot measures failed. Last November, Washington voters narrowly rejected a mandate to label GMO foods. Backers blamed the defeat on a record $22 million raised by labeling opponents, including large biotech corporations and food manufacturers. Supporters raised about $8.1 million.

A ballot measure also didn’t make it in California in 2012, where pro-labeling activists were equally outspent by biotechnology companies. Biotech firms raised $45 million in that state, while consumer advocates and organic food makers raised just $9 million.

In Oregon, a GMO labeling initiative was defeated in 2002. However, concerns over GMO’s in Oregon regained momentum two years ago, when some organic farmers in the southern part of the state discovered genetically altered beets were being grown near their fields.

Farmers in several counties pushed for measures to ban genetically modified crops, though only the initiative in Jackson County made it to the ballot. Voters will decide whether to ban GMO crops in that county next week.

Hoping to forestall a patchwork of local regulations, Oregon enacted legislation barring counties from adopting GMO bans. Oregon Gov. John Kitzhaber also created a task force on genetically engineered agriculture and directed the state’s Department of Agriculture to examine issues surrounding GMO crops, including labeling.

Currently, there’s little science that says genetically engineered foods are unsafe. But labeling proponents say too much is still unknown about GMO’s, so consumers have a right to know if they are eating them.

“GMO’s are not systematically, independently tested for safety before they’re sold to consumers, so we should give Oregonians the ability to decide for themselves,” said David Rosenfeld, executive director of the state’s consumer group OSPIRG.

Labeling critics say mandatory labels would mislead consumers into thinking that engineered ingredients are unsafe. And though most GM crops are engineered for resistance to herbicides or insects, advocates say engineering could eventually make crops more nutritious, resistant to disease, or tolerable of drought or other weather calamities.

In an effort to head off state-by-state efforts to require mandatory labeling of GMO foods, the food industry has recently proposed voluntary labeling of engineered foods. The industry is pushing a House bill in Congress that would create new voluntary labels nationwide.

GMO crops are common in the U.S. The vast majority of processed foods contain GMOs and over 80 percent of the corn and more than 90 percent of the soybeans planted in the U.S. are genetically modified. The FDA could soon approve a genetically modified salmon.